Search results for ""

It’s here at last: the fourth and final installment of our series on core sentence structure! I recommend reading all of the installments in order, starting with part 1.

Try out this GMATPrep® problem from the free exams.

* “The greatest road system built in the Americas prior to the arrival of Christopher Columbus was the Incan highway, which, over 2,500 miles long and extending from northern Ecuador through Peru to southern Chile.

“(A) Columbus was the Incan highway, which, over 2,500 miles long and extending

“(B) Columbus was the Incan highway, over 2,500 miles in length, and extended

“(C) Columbus, the Incan highway, which was over 2,500 miles in length and extended

“(D) Columbus, the Incan highway, being over 2,500 miles in length, was extended

“(E) Columbus, the Incan highway, was over 2,500 miles long, extending”

The First Glance in this question is similar to the one from the second problem in the series. Here, the first two answers start with a noun and verb, but the next three insert a comma after the subject. Once again, this is a clue to check the core subject-verb sentence structure.

First, strip down the original sentence:

Here’s the core:

The greatest road system was the Incan highway.

(Technically, greatest is a modifier, but I’m leaving it in because it conveys important meaning. We’re not just talking about any road system. We’re talking about the greatest one in a certain era.)

The noun at the beginning of the underline, Columbus, is not the subject of the sentence but the verb was does turn out to be the main verb in the sentence. The First Glance revealed that some answers removed that verb, so check the remaining cores.

“(B) The greatest road system was the Incan highway and extended from Ecuador to Chile.

“(C) The greatest road system.

“(D) The greatest road system was extended from Ecuador to Chile.

“(E) The greatest road system was over 2,500 miles long.”

Answer (C) is a sentence fragment; it doesn’t contain a main verb. The other choices do contain valid core sentences, though answers (B) and (D) have funny meanings. Let’s tackle (B) first.

“(B) The greatest road system was the Incan highway and extended from Ecuador to Chile.

When two parts of a sentence are connected by the word and, those two parallel pieces of information are not required to have a direct connection:

Yesterday, I worked for 8 hours and had dinner with my family.

Those things did not happen simultaneously. One did not lead to the other. They are both things that I did yesterday, but other than that, they don’t have anything to do with each other.

In the Columbus sentence, though, it doesn’t make sense for the two pieces of information to be separated in this way. The road system was the greatest system built to that point in time because it was so long. The fact that it extended across all of these countries is part of the point. As a result, we don’t want to present these as separate facts that have nothing to do with each other. Eliminate answer (B).(more…)

Welcome to the third installment of our Core Sentence series. In part 1, we began learning how to strip an SC sentence (or any sentence!) down to the core sentence structure. In part 2, we took a look at a compound sentence structure.

Today, we’re going to look at yet another interesting sentence structure that is commonly used on the GMAT.

Try out this GMATPrep® problem from the free exams. (Note: as in the previous installments, I’m going to discuss aspects of our SC Process; if you haven’t learned it already, read about it before doing this problem.)

* “Many financial experts believe that policy makers at the Federal Reserve, now viewing the economy as balanced between moderate growth and low inflation, are almost certain to leave interest rates unchanged for the foreseeable future.

“(A) Reserve, now viewing the economy as balanced between moderate growth and low inflation, are

“(B) Reserve, now viewing the economy to be balanced between that of moderate growth and low inflation and are

“(C) Reserve who, now viewing the economy as balanced between moderate growth and low inflation, are

“(D) Reserve, who now view the economy to be balanced between that of moderate growth and low inflation, will be

“(E) Reserve, which now views the economy to be balanced between moderate growth and low inflation, is”

The First Glance didn’t tell me a lot on this one. In each case, there appears to be some kind of modifier going on, signaled either by the who / which language or by the comma, but I don’t have a good idea of what’s being tested. Time to read the sentence.

I don’t know about you, but the original sentence really doesn’t sound good to me. The difficulty, though, is that I don’t know exactly why. I just find myself thinking, “Ugh, I wouldn’t say it that way.”

Specifically, I don’t like the “now viewing” after the comma…but when I examined it a second time, I couldn’t find an actual error. That’s a good clue to me that I need to leave the answer in; they’re just trying to fool my ear (and almost succeeding!).

Because I’m not certain what to examine and because I know that there may be something going on with modifiers, I’m going to strip the original sentence down to the core:

Here’s the core:

Many experts believe that policy makers are almost certain to leave interest rates unchanged.

This sentence uses what we call a “Subject-Verb-THAT” structure. When you see the word that immediately after a verb, expect another subject and verb (and possibly object) to come after. The full core will be Subject-Verb-THAT-Subject-Verb(-Object).

Back to the problem: notice where the underline falls. The Subject-Verb-THAT-Subject part is not underlined, but the second verb is, and it’s the last underlined word. Check the core sentence with the different options in the answers:

Many experts believe that policy makers __________ almost certain to leave rates unchanged.

(A) Many experts believe that policy makers are almost certain to leave rates unchanged.

(B) Many experts believe that policy makers and are almost certain to leave rates unchanged.

(C) Many experts believe that policy makers.

(D) Many experts believe that policy makers will be almost certain to leave rates unchanged.

(E) Many experts believe that policy makers is almost certain to leave rates unchanged.

Excellent! First, answer (E) is wrong because it uses a singular verb to match with the plural policy makers.

Next, notice that answer (B) tosses the conjunction and into the mix. A sentence can have two verbs, in which case you could connect them with an and, but this answer just tosses in a random and between the subject and the verb. Answer (B) is also incorrect.

Answer (C) is tricky! At first, it might look like the core is the same as answer (A)’s core. It’s not. Notice the lack of a comma before the word who. Take a look at this example:

The cat thought that the dog who lived next door was really annoying.

What’s the core sentence here? This still has a subject-verb-THAT-subject-verb(-object) set-up. It also has a modifier that contains its own verb—but this verb is not part of the core sentence:

The cat thought that the dog [who lived next door] was really annoying.

Answer (C) has this same structure:

Many experts believe that policy makers [who are almost certain to leave rates unchanged]…

Where’s the main verb that goes with policy makers? It isn’t there at all. Answer (C) is a sentence fragment.

We’re down to answers (A) and (D). Both cores are solid, so we’ll have to dig a little deeper. So far, we’ve been ignoring the modifier in the middle of the sentence. Let’s take a look; compare the two answers directly:

“(A) Reserve, now viewing the economy as balanced between moderate growth and low inflation, are

“(D) Reserve, who now view the economy to be balanced between that of moderate growth and low inflation, will be”

Probably the most obvious difference is are vs. will be. I don’t like this one though because I think either tense can logically finish the sentence. I’m going to look for something else.

There are two other big differences. First, there’s an idiom. Is it view as or view to be? If you’re not sure, there’s also a comparison issue. Is the economy balanced between growth and inflation? Or between that of growth and inflation?

The that of structure should be referring to another noun somewhere else: She likes her brother’s house more than she likes that of her sister. In this case, that of refers to house.

What does that of refer to in answer (D)?

I’m not really sure. The economy? The Federal Reserve? These don’t make sense. The two things that are balanced are, in fact, the growth and the inflation; that of is unnecessary. Answer (D) is incorrect.

The correct answer is (A).

The correct idiom is view as, so answers (B), (D), and (E) are all incorrect based on the idiom.

Key Takeaways: Strip the sentence to the Core

(1) When you see the word that immediately following a verb, then you have a Subject-Verb-THAT-Subject-Verb(-Object) structure. Check the core sentence to make sure that all of the necessary pieces are present. Also make sure, as always, that the subjects and verbs match.

(2) If you still have two or more answers left after dealing with the core sentence, then check any modifiers. The two main modifier issues are bad placement (which makes them seem to be pointing to the wrong thing) or meaning issues. In this case, the modifier tossed in a couple of extraneous words that messed up the meaning of the between X and Y idiom.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.

Welcome to the second installment of our Core Sentence series; if you haven’t yet read Part 1, do so now before continuing with this segment. How has your practice been going? It’s hard to develop the ability to “grey out” parts of the sentence in your mind. Did you find that you were able to do so without writing anything down? Or did you find that the technique solidified better when you did write out the core sentence?

Most people do have to start, in practice, by writing out the core. The goal is to be able to do everything (or almost everything) in your head by the time the real test rolls around.

Try out this GMATPrep® problem from the free exams; give yourself about 1 minute 20 seconds. (You can always choose to spend a little longer, since that time is an average, not a limit; more than about 20-30 seconds longer, though, typically just indicates that you’ve gotten stuck. At that point, guess from among the remaining answers and move on.)

* “Galileo did not invent the telescope, but on hearing, in 1609, that such an optical instrument had been made, he quickly built his own device from an organ pipe and spectacle lenses.

“(A) Galileo did not invent the telescope, but on hearing, in 1609, that such an optical instrument had been made, he

“(B) Galileo had not invented the telescope, but when he heard, in 1609, of such an optical instrument having been made,

“(C) Galileo, even though he had not invented the telescope, on hearing, in 1609, that such an optical instrument had been made, he

“(D) Even though Galileo did not invent the telescope, on hearing, in 1609, that such an optical instrument had been made,

“(E) Even though Galileo did not invent the telescope, but when he heard, in 1609, of such an optical instrument being made, he”

The First Glance shows a possible sentence structure issue: The first two start with a noun and verb, while the third tosses in a comma after that subject. I’m definitely going to need to check for that verb later!

The final two start with even though, which signals a clause, but a dependent one. That means I’ll have to make sure there’s an independent clause (complete sentence) somewhere later on.

Time to read the original sentence. It’s decently complex. What’s the core sentence?

Here’s the core:

Galileo did not invent the telescope, but he built his own device.

This actually consists of two complete sentences connected by a “comma and” conjunction. There’s nothing wrong with the core on this one. Now, you have a choice. You can check the modifiers in the original sentence (and, indeed, if you did spot any problems, you’d want to go deal with those right away). If not, though, then start with those potential structure issues spotted during the first glance.

Strip out the core for the other four answers:

“(B) Galileo had not invented the telescope, but quickly built his own device.

“(C) Galileo he quickly built his own device.

“(D) Even though Galileo did not invent the telescope, quickly built his own device.

“(E) Even though Galileo did not invent the telescope, but he quickly built his own device.”

Excellent! Now we have something to work with! Answer (C) doubles the subject; we don’t need to say both Galileo and he.

Answers (D) and (E) both start with even though, creating a dependent clause. Answer (D) doesn’t have an independent clause later because the part after the comma is missing the subject he.

Note: answer (B) might appear to have the same problem as (D), but the structures are not the same. Answer (B) begins with an independent clause. In this case, it’s okay to say the subject only once at the beginning and then attach two different verbs (had not invented and built) to that subject. (You may still think this one sounds funny. More on this below.)

Answer (E) does have an independent clause later, but there’s a meaning problem. The word but already indicates a contrast. Using both even though and but to connect the two parts of the sentence is redundant.

Okay, (C), (D) and (E) have all been eliminated. Now, compare (A) and (B) directly.

“(A) Galileo did not invent the telescope, but on hearing, in 1609, that such an optical instrument had been made, he

“(B) Galileo had not invented the telescope, but when he heard, in 1609, of such an optical instrument having been made,”

There are a couple of different ways to tackle this, but I’m going to stick to the sentence structure route, since that’s our theme today. Answer (B) does have one more clause in it, though it’s a dependent clause:

“Galileo had not invented the telescope, but when he heard of such an optical instrument having been made, quickly built his own device.”

Now, we do have a problem with the structure! If that intervening dependent clause weren’t there at all, then the core could have been okay: Subject verb, but verb. Technically, you wouldn’t want a comma there, but that’s really the only small issue.

When, however, you introduce a dependent clause in the middle, you can’t carry that original subject, Galileo, all the way over to the second verb at the end. Instead, as with answer (D), you need a complete sentence after the dependent clause, something like:

Galileo did not invent the telescope, but when he heard that one had been made, HE quickly built his own device.

Answer (B) is also incorrect.

The correct answer is (A).

You’re halfway through! Join me next time, when we’ll take a look at another type of complex sentence structure used commonly on the GMAT.

Key Takeaways: Strip the sentence to the Core, part 2

(1) In the Galileo problem, only the correct answer contains a “legal” core sentence. Though there are other ways to eliminate answers on this problem, you still need to learn how to deal with structure. GMAC (the organization that makes the GMAT) has said for several years now that they are including more SC problems in which you really do have to understand the underlying meaning or sentence structure in order to get yourself all the way down to the right answer.

(2) Complex sentence structures can come in many flavors. One of the most common is the compound sentence, which consists of at least two complete sentences connected by a “comma + conjunction” or a semi-colon. The comma conjunction” structure will use the FANBOYS (For And Nor But Or Yes So). You can learn more about the FANBOYS in chapter 3 (Sentence Structure) of our 6th edition Sentence Correction Strategy Guide.

(3) A sentence can also contain dependent clauses (and the complicated sentences we see on the GMAT often do). Common words that signal a dependent clause include although, if, since, that, unless, when, and while. You can learn more about these in chapter 4 (Modifiers) of our 6ED SC guide.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.

Recently, I was discussing sentence structure with one of my classes and we practiced a crucial but difficult GMAT skill: how to strip an SC sentence to its core components. Multiple OG problems can be solved just by eliminating faulty sentence cores—and the real GMAT is testing this skill today more than we see in the published materials.

So I’m going to write a series of articles on just this topic; welcome to part 1 (and props to my Wednesday evening GMAT Fall AA class for inspiring this series!).

Try out this GMATPrep® problem from the free exams. (Note: in the solution, I’m going to discuss aspects of our SC Process; if you haven’t learned it already, go read about it right now, then come back and try this problem.)

* “With surface temperatures estimated at minus 230 degrees Fahrenheit, Jupiter’s moon Europa has long been considered far too cold to support life, and with 60 square miles of water thought to be frozen from top to bottom.

“(A) Europa has long been considered far too cold to support life, and with

“(B) Europa has long been considered far too cold to support life, its

“(C) Europa has long been considered as far too cold to support life and has

“(D) Europa, long considered as far too cold to support life, and its

“(E) Europa, long considered to be far too cold to support life, and to have”

The First Glance does help on this one, but only if you have studied sentence structure explicitly. Before I did so, I used to think: “Oh, they started with Europa because they added a comma in some answers, but that doesn’t really tell me anything.”

But I’ve learned better! What is that comma replacing? Check it out: the first three answers all have a verb following Europa. The final two don’t; that is, the verb disappears. That immediately makes me suspect sentence structure, because a sentence does have to have a verb. If you remove the main verb from one location, you have to put one in someplace else. I’ll be watching out for that when I read the sentence.

And now it’s time to do just that. As I read the sentence, I strip it down to what we call the “sentence core” in my mind. It took me a long time to develop this skill. I’ll show you the result, first, and then I’ll tell you how I learned to do it.

The “sentence core” refers to the stuff that has to be there in order to have a complete sentence. Everything else is “extra”: it may be important later, but right now, I’m ignoring it.

I greyed out the portions that are not part of the core. How does the sentence look to you?

Notice something weird: I didn’t just strip it down to a completely correct sentence. There’s something wrong with the core. In other words, the goal is not to create a correct sentence; rather, you’re using certain rules to strip to the core even when that core is incorrect.

Using this skill requires you to develop two abilities: the ability to tell what is core vs. extra and the ability to keep things that are wrong, despite the fact that they’ll make your core sound funny. The core of the sentence above is:

Europa has long been considered too cold to support life, and.

Clearly, that’s not a good sentence! So why did I strip out what I stripped out, and yet leave that “comma and” in there? Here was my thought process:

Text of sentence

My thoughts:

“With…”

Preposition. Introduces a modifier. Can’t be the core.

“With surface temperatures estimatedat minus 230 degrees Fahrenheit,”

Each word I’ve italicized introduces a new noun modifier. Nothing here is a subject or main verb. *

“Jupiter’s moon Europa”

The main noun is Europa; ignore the earlier words.

“Europa has long been considered far too cold to support life,”

That’s a complete sentence. Yay.

“, and”

A complete sentence followed by “comma and”? I’m expecting another complete sentence to follow. **

“with 60 square miles of water thought to be frozen from top to bottom.”

Same deal as the beginning of the sentence! Each word I’ve italicized introduces a new modifier. Nothing here that can function as a subject or main verb.

* Why isn’t estimated a verb?

Estimated is a past participle and can be part of a verb form, but you can’t say “Temperatures estimated at minus 230 degrees Fahrenheit.” You’d have to say “Temperatures are estimated at…” (Note: you could say “She estimated her commute to be 45 minutes from door to door.” In other words, estimated by itself can be the main verb of a sentence. In my example, though, the subject is actually doing the estimating. In the GMATPrep problem above, the temperatures can’t estimate anything!)

** Why is it that I expected another complete sentence to follow the “comma and”?

The word and is a parallelism marker; it signals that two parts of the sentence need to be made parallel. When you have one complete sentence, and you follow that with “comma and,” you need to set up another complete sentence to be parallel to that first complete sentence.

For example:

She studied all day, and she went to dinner with friends that night.

The portion before the and is a complete sentence, as is the portion after the and.

(Note: the word and can connect other things besides two complete sentences. It can connect other segments of a sentence as well, such as: She likes to eat pizza, pasta, and steak. In this case, although there is a “comma and” in the sentence, the part before the comma is not a complete sentence by itself. Rather, it is the start of a list.)

Okay, so my core is:

Europa has long been considered too cold to support life, and.

And that’s incorrect. Eliminate answer (A). Either that and needs to go away or, if it stays, I need to have a second complete sentence. Since you know the sentence core is at issue here, check the cores using the other answer choices:

Here are the cores written out:

“(B) Europa has long been considered too cold to support life.

“(C) Europa has long been considered as too cold to support life and has 60 square miles of water.

“(D) Europa and its 60 square miles of water.

“(E) Europa.”

(On the real test, you wouldn’t have time to write that out, but you may want to in practice in order to build expertise with this technique.)

Answers (D) and (E) don’t even have main verbs! Eliminate both. Answers (B) and (C) both contain complete sentences, but there’s something else wrong with one of them. Did you spot it?

The correct idiom is consider X Y: I consider her intelligent. There are some rare circumstances in which you can use consider as, but on the GMAT, go with consider X Y. Answers (C), (D), and (E) all use incorrect forms of the idiom.

Answer (C) also loses some meaning. The second piece of information, about the water, is meant to emphasize the fact that the moon is very cold. When you separate the two pieces of information with an and, however, they appear to be unrelated (except that they’re both facts about Europa): the moon is too cold to support life and, by the way, it also has a lot of frozen water. Still, that’s something of a judgment call; the idiom is definitive.

Key Takeaways: Strip the sentence to the Core

(1) Generally, this is a process of elimination: you’re removing the things that cannot be part of the core sentence. With rare exceptions, prepositional phrases typically aren’t part of the core. I left the prepositional phrase of water in answers (C) and (D) because 60 square miles by itself doesn’t make any sense. In any case, prepositional phrases never contain the subject of the sentence.

(2) Other non-core-sentence clues: phrases or clauses set off by two commas, relative pronouns such as which and who, comma + -ed or comma + ing modifiers, -ed or –ing words that cannot function as the main verb (try them in a simple sentence with the same subject from the SC problem, as I did with temperatures estimated…)

(3) A complete sentence on the GMAT must have a subject and a working verb, at a minimum. You may have multiple subjects or working verbs. You could also have two complete sentences connected by a comma and conjunction (such as comma and) or a semi-colon. We’ll talk about some additional complete sentence structures next time.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.

Try out the First Glance on the below problem and see what happens! This is a GMATPrep® problem from the free exams.

* “Most of the purported health benefits of tea comes from antioxidants—compounds also found in beta carotene, vitamin E, and vitamin C that inhibit the formation of plaque along the body’s blood vessels.

“(A) comes from antioxidants—compounds also found in beta carotene, vitamin E, and vitamin C that

“(B) comes from antioxidants—compounds that are also found in beta carotene, vitamin E, and vitamin C, and they

“(C) come from antioxidants—compounds also found in beta carotene, vitamin E, and vitamin C, and

“(D) come from antioxidants—compounds that are also found in beta carotene, vitamin E, and vitamin C and that

“(E) come from antioxidants—compounds also found in beta carotene, vitamin E, and vitamin C, and they”

The First Glance definitely helps on this one: comes vs. come is a singular vs. plural verb split, indicating a subject-verb agreement issue. Now, when you read the original sentence, you know to find the subject.

So what is the subject of the sentence? It’s not the singular tea, though it’s tempting to think so. The subject is actually the word most, which is a SANAM pronoun.

The SANAM pronouns: Some, Any, None, All, More / Most

These pronouns can be singular or plural, depending on the context of the sentence. Consider these examples:

The first step of the SC process is a First Glance, something that didn’t help out a whole lot on last week’s problem. Let’s try out the First Glance again and see what happens!

This GMATPrep® problem is from the free exams.

* “Often incorrectly referred to as a tidal wave, a tsunami, a seismic sea wave that can reach up to 150 miles per hour in speed and 200 feet high, is caused by underwater earthquakes or volcanic eruptions.

“(A) up to 150 miles per hour in speed and 200 feet high, is

“(B) up to 150 miles per hour in speed and heights of up to 200 feet, is

“(C) speeds of up to 150 miles per hour and 200 feet high, are

“(D) speeds of up to 150 miles per hour and heights of up to 200 feet, is

“(E) speeds of up to 150 miles per hour and as high as 200 feet, are”

What did you do for the First Glance? The glance is designed to give you an upfront hint about one issue that the sentence might be testing before you actually start reading the full sentence. Take a look at the beginning of the underline, including the beginning of all five answer choices.

The split is between up to and speeds of up to. There isn’t an obvious grammar rule here, so the issue is likely to revolve around meaning: do we need to say speeds of or is it enough to say just up to?

Think about this while reading the original sentence. What do you think?

The phrase reach up to could go in several different directions—is it going to say up to 150 miles in length? up to 150 feet high?—so it’s preferable to clarify right up front that the wave is reaching speedsof up to 150 miles per hour.

In addition, the sentence contains parallelism:

can reach up to X [150 miles per hour in speed] and Y [200 feet high]

The portion before the parallelism starts must apply to both the X and Y portions, so the original sentence says:

can reach up to 200 feet high

That might sound kind of clunky and it is: up to and high are redundant.

Okay, answer (A) is incorrect and answer (B) repeats both issues (it neglects to specify speeds of up to 150 and it contains faulty parallelism.).

Check the parallelism in the other choices:

“(C) speeds of up to [150 miles per hour] and [200 feet high]

“(D) [speeds of up to 150 miles per hour] and [heights of up to 200 feet]

“(E) speeds of [up to 150 miles per hour] and [as high as 200 feet]”

In answer (C), the Y portion is the measurement (200 feet), so the X portion should also be the measurement…but it’s nonsensical to say speeds of up to 200 feet high. Likewise, in (E), the Y portion is a prepositional phrase, so it matches the prepositional phrase in the X portion. Now, the sentence says speeds of as high as 200 feet—equally nonsensical.

The only one that makes sense is answer (D): speeds of up to 150 and heights of up to 200.

The correct answer is (D).

You might also have noticed, in the original sentence, that the last underlined word is the verb is. Sentence Correction problems always have at least one difference at the beginning of the underline and at the end, so glance down the end of the choices.

Interesting! Is vs. are. What subject goes with this verb? Here’s the original sentence again:

“Often incorrectly referred to as a tidal wave, a tsunami, a seismic sea wave that can reach up to 150 miles per hour in speed and 200 feet high, is caused by underwater earthquakes or volcanic eruptions.”

The modifiers have been crossed out. The subject is tsunami, a singular noun, so the verb should be the singular is. Answers (C) and (E) are incorrect for this reason.

Key Takeaways: The First Glance in Sentence Correction

(1) Before reading the original sentence, make it a habit to glance at the word or couple of words at the start of the underline and each answer choice. Sometimes, the split will be obvious: an is vs. are split, for example, clearly indicates subject-verb agreement.

(2) Sometimes the split will be less obvious, as with up to vs. speeds of up to. In this case, if the split is fairly easy to remember, just keep the variations in mind as you read the original sentence, so that you can analyze the difference right away. You may see immediately that speeds of up to is more clear, and your knowledge that the sentence is testing this meaning might also alert you to some of the meaning issues introduced by the faulty parallelism.

(3) Making a subject-verb match in the midst of a bunch of modifiers can be tricky. Learn how to strip the modifiers out and take the sentence down to its basic core structure.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.

On some Sentence Correction (SC) problems, an error jumps out at you immediately. On others, you’re left trying to figure out where to start. How do you dig in when the starting point isn’t obvious?

Try this GMATPrep® problem from the free exams and then we’ll talk about it.

* “A recording system was so secretly installed and operated in the Kennedy Oval Office that even Theodore C. Sorensen, the White House counsel, did not know it existed.

“(A) A recording system was so secretly installed and operated in the Kennedy Oval Office that

“(B) So secret was a recording system installation and operation in the Kennedy Oval Office

“(C) It was so secret that a recording system was installed and operated in the Kennedy Oval Office

“(D) A recording system that was so secretly installed and operated in the Kennedy Oval Office

“(E) Installed and operated so secretly in the Kennedy Oval Office was a recording system that”

The first step on SC is to glance at the start of the underline (even before you read the sentence) in order to see whether the opening change in the answers gives you a clue about where to start. In this case, the underline starts right at the beginning of the sentence. A scan down the beginning of each answer choice signals exactly nothing on this problem. Now what?

Okay, on to step 2: read the original sentence (for both meaning and grammar). What do you think?

The sentence sounds kind of clunky. It uses an idiom (so X thatY). Is the idiom used correctly? Here are some correct examples.

She was SO extraordinarily lucky THAT she actually won the lottery three separate times.

The CEO was SO preoccupied with profits THAT he missed the signs of a market collapse.

Notice the structure in these examples. There are actually two subject-and-verb pairs—one set before the word that and one set after. In addition, the Y portion of the sentence (after that) represents evidence to support the scenario in X or some consequence of that scenario. The fact that she won the lottery three times is evidence that she’s really lucky. The CEO’s preoccupation actually caused the CEO to miss signs of the collapse.

The original sentence has this same structure:

(A) The system was SO secretly installed THAT even Sorensen did not know it existed.

This structure, then, is correct in the original sentence. What about the other answers?

Here’s where things start to get messy! Strip down the structures for each choice:

(B) SO secret was the system (even Sorensen did not know it existed.)

(C) It was SO secret THAT a system was installed (even Sorensen did not know it existed.)

(D) A system that was SO secretly installed (even Sorensen did not know it existed.)

(E) Installed SO secretly was a system THAT (even Sorensen did not know it existed.)

Answer (B) is missing the that portion of the idiom. People often skip this word in real life but notice what happens when you do so:

She was so late, I wasn’t even sure she was coming!

There are two complete sentences connected only by a comma. That’s a comma splice error! Eliminate (B).

Answer (D) does have the word that, but it’s before the so. This sentence turns out to have no main verb for the subject (system). That was so secretly installed modifies system, and even Sorensen… doesn’t provide a verb for system. Eliminate (D).

In both cases, the missing that signaled a problem with sentence structure.

Answer (C) has the that…but wait a second. It moved. Is it still okay?

No! That a system was installed is just a modifier of secret; it’s not actually finishing off the idiom by providing some follow-on info or consequence of the so portion. There should still be a that before even Sorensen:

It was SO secret that a system was installed THAT even Sorensen did not know it existed.

(That sentence may still sound clunky to you. The double that may be tripping your “sounds bad!” instincts, or possibly the passive It was opening. I definitely wouldn’t write the sentence this way myself!)

Eliminate (C). Okay, what about answer (E)?

The soX portion of the sentence should provide the opening information that is later addressed in the that Y portion. What was so surprising that Sorensen didn’t know?

The surprise was that this system had been installed and was being operated in the area where he worked. In answer (E), though, those verbs come before the so—that is, they are not part of the X portion of the sentence. Eliminate (E).

Only answer (A) uses the idiom to convey the proper meaning: This system was SO secretly installed and operated THAT even someone who worked there didn’t know about it!

The correct answer is (A).

Key Takeaways: Meaning, Structure, and Idioms in SC

(1) When you don’t spot an obvious way into the sentence, consider examining the core sentence, particularly if the sentence contains a structure that extends across nearly the whole thing, such as parallelism or an idiom (as in this case).

(2) Messing up an idiom can lead to both meaning and structure errors. Even if you don’t know the idiom, then, you might still be able to narrow down the answers! In the problem above, answer (B) was a run-on and answer (D) was a fragment, all because the usage of the idiom was messed up.

(3) Stripping the sentence down to the minimum necessary to test the sentence (and idiom) structure takes some time but may be your best shot at answering the question. This may not get you all the way to the right answer, but there’s a good chance it will help you eliminate some wrong answers.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.

Welcome to the final installment in a series of three articles about meaning and sentence structure in sentence correction. Our first one tested meaning and also covered issues related to having to break the sentence into chunks. In the second, we talked about how to use that chunk idea to strip the sentence down to the core structure vs. the modifiers.

Today, I’ve got a third GMATPrep® problem for you following some of these same themes (I’m not going to tell you which ones till after you’ve tried the problem!).

* “Today’s technology allows manufacturers to make small cars more fuel-efficient now than at any time in their production history.

“(A) small cars more fuel-efficient now than at any time in their

“(B) small cars that are more fuel-efficient than they were at any time in their

“(C) small cars that are more fuel-efficient than those at any other time in

“(D) more fuel-efficient small cars than those at any other time in their

“(E) more fuel-efficient small cars now than at any time in”

The first glance doesn’t indicate a lot this time. The answers change from small cars to more (fuel-efficient small cars), which isn’t much of a clue. Go ahead and read the original sentence.

What did you think? When I first read it, I shrugged and thought, “That sounds okay.” If you can’t come up with something to tackle from the first glance or the first read-through, then compare answers (A) and (B), looking for differences.

Hmm. I see—do we need to say that are more fuel-efficient? Maybe. Answer (C) uses that same structure. Oh, hey, answer (C) tosses in the word other! I know what they’re doing!

If you’ve seen the word other tested within a comparison before, you may know, too. If not, get ready to make a note. Take a look at these two sentences:

Try this GMATPrep® problem from the free exams and then we’ll talk about it.

* “The striking differences between the semantic organization of Native American languages and that of European languages, in both grammar and vocabulary, have led scholars to think about the degree to which differences in language may be correlated with nonlinguistic differences.

“(A) that of European languages, in both grammar and vocabulary, have

“(B) that of European languages, including grammar and vocabulary, has

“(C) those of European languages, which include grammar and vocabulary, have

“(D) those of European languages, in grammar as well as vocabulary, has

“(E) those of European languages, both in grammar and vocabulary, has”

At first glance, the underline isn’t super long on this one, Glance down the first word of each answer. What does a split between that and those signify?

Both are pronouns, so they’re referring to something else in the sentence. In addition, one is singular and one is plural, so it will be important to find the antecedent (the word to which the pronoun refers).

Next, read the original sentence. What do you think? It isn’t super long but it still manages to pack in some complexity. Learn how to strip it down and you’ll be prepared for even more complex sentence structures.

My first thought was: okay, now I see why they offered that vs. those. Should the pronoun refer to the plural differences or to the singular organization?

It could be easy to get turned around here, so strip down the sentence structure:

What is the OGSC (for short)?

It’s one of the best GMAT study guides you could have (if we do say so ourselves)!

Here’s the deal: nearly everyone studies from The Official Guide for GMATÒ Review, 13th Edition (or OG13). This book contains about 900 real GMAT questions that appeared on the exam in the past. OG13 does contain explanations, but those explanations are “textbook” explanations: reading them is like reading a grammar book. The answers are completely accurate but a bit hard to follow if you’re not a grammar teacher (and some of them are hard to follow even when you are a grammar teacher… ahem).

So we decided to remedy that problem by writing our own explanations for every single one of the 159 Sentence Correction problems contained in OG13. We’ll tell you the SC Process for getting through any SC question efficiently and effectively. We’ll also discuss how to eliminate each wrong answer in terms that are easy for students (not just teachers) to understand. The book includes an extra section on sentence structure and a glossary of common grammar terms. Finally, you’ll gain access to our online GMAT Navigator program which lets you track your OG work, time yourself, and view your performance data so that you can better determine your strengths and weaknesses.

Who should use the OGSC?

Are you struggling to improve your SC performance? Do you love studying official problems but hate trying to decipher the sometimes-mystifying official explanations? Do you want to throw your OG13 across the room when you read yet another explanation that says an answer choice is “wordy” or “awkward”?

If something is “awkward,” there is a real reason why—and we explain that specific reason to you so that you can start to pick out similar faulty constructions on other problems in future. (Did you know that, most of the time, “wordy” and “awkward” are code words for an ambiguous or illogical meaning? The OGSC will help you learn how to decipher these for yourself!)

How can I get the most out of the OGSC?

First, read the introduction chapter, where you’ll learn all about how to work through an SC problem in an efficient manner.

Next, if you have already started studying Sentence Correction problems from the OG, begin with the problems that you’ve tried recently. Try to articulate to yourself why each of the four wrong answers is wrong. Try to find all of the errors in each answer (though, on the real test, just one error is enough to eliminate an answer!).

Note: You don’t need to use grammar terminology when you’re trying to articulate why something’s wrong, but do try to go beyond “this one sounds bad.” That’s a good starting point but which part, specifically, sounds bad? What sounds so bad about that part?

Then, check yourself against the explanations. If you didn’t spot a particular error, go back to the problem and ask yourself what clues (in the form of differences in the answer choices) will alert you the next time this particular topic is being tested. If you didn’t know how to handle the issue but now understand from the explanation, make yourself a flashcard to help you remember whatever that is for future. If the explanation seems like Greek to you, then maybe this particular issue is too hard and your take-away is to skip something like this in future and make a guess!

When you’re ready to try new OG problems, make sure to do them under timed conditions (try to average about 1 minute 20 seconds on SC). When you’re done, check the answer. If you guessed, go ahead straight to the explanation. If you got it right, try to articulate why each incorrect answer is wrong, then check the explanation. If you got it wrong, look at the problem again to see whether you might have made a careless mistake. Then go to the explanation.